1. Field of the Invention
The present invention relates to a communication apparatus or a communication method between the communication apparatuses.
2. Description of the Related Art
In recent years, the need for the virtualization of a network is increasing for a network infrastructure with the evolution of the virtualization of a server. It is necessary to connect multiple virtual machines in a data center, further accommodate tenants of multiple client systems in the same infrastructure, and disable communication between the tenants. In order to provide flexibility to the placement and operation of resources of the virtual machines, a large-scale Layer 2 network is to be assigned to each tenant. If a large-scale Layer 2 network is constructed between remote locations such as between data centers, a Layer 3 network may be interposed. In order to deal with this request, there are overlay technologies that stretch Layer 2 networks via Layer 3 networks.
IETF RFC7348 “Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks”, ISSN: 2070-1721 Published in August 2014 discloses the VXLAN technology that realizes a Layer 2 multitenant environment of approximately 16 million on a Layer 3 network. According to the technology described in IETF RFC7348 “Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks”, ISSN: 2070-1721 Published in August 2014, one virtual tunnel endpoint (VTEP) is provided to a virtual switch or the like in each physical server. The VTEP encapsulates a layer 2 frame in a Layer 3 packet, and transmits the encapsulated packet to a VTEP to which a destination virtual machine belongs. Upon the encapsulation, a virtual network identifier (VNI) identifying a tenant is added in the packet. The VTEP that has received the packet determines a forwarding destination after decapsulation from the VNI and a destination MAC address of the inner layer 2 frame, and forwards the packet or discards it if there is no destination. A Layer 3 IP address is used for forwarding. Accordingly, Layer 3 ECMP (Equal Cost Multipath) may be used to extend a bandwidth. A source IP address and a destination IP address of an IP header to be encapsulated are the same. Therefore, in order to make effective use of Layer 3 ECMP when communication is carried out between specific VTEPs, it is recommended to have a source port number of an UDP header being a hash of the inner Ethernet frame's header.
IETF RFC7365 “Framework for Data Center (DC) Network Virtualization” ISSN: 2070-1721, Published on October 2014 describes a framework for data center network virtualization over a Layer 3 network. According to the framework described in IETF RFC7348 “Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks”, ISSN: 2070-1721 Published in August 2014, a method that connects tenant systems to VNIs is described. There is a VTEP in a packet relay apparatus such as a virtual switch or physical switch, and there is a VNI belonging to the VTEP. A virtual access point that connects the VNI to a tenant system is, for example, an interface identifier connected to a physical port or VLAN of a physical switch, or a virtual machine of a virtual switch.
JP-A-2014-230057 discloses a technology that selects communication on a network corresponding to a specific quality of service (QoS) from a plurality of networks with different QoSs in communication between virtual machines. When L2 over L3 tunneling communication is carried out between virtual machines operating on different physical servers, there is a plurality of networks with different QoSs between the physical servers. When a first virtual machine makes a communication addressed to a second virtual machine, used is an IP address of a physical network that supports a specific QoS for an IP address of an L3 packet of when an L2 frame is encapsulated in the L3 packet.